Background: Acute kidney injury (AKI) incidence is reported to be 10 times higher in aged people. Related to their higher prevalence of chronic kidney disease (CKD), older patients are at high risk of toxic effects driven by drugs. Methods: The demographics, hospitalizations, visits to the Emergency Department, pharmacological therapy, and lab tests were analyzed in 71,588 individuals. Results: Data showed a higher prevalence of AKI as well as CKD in the elderly as compared to the younger group, with an associated very high mortality. A broad number of drugs was prescribed, ranging from 1 to 35, the majority being between 5 and 9 drugs. Conclusion: Elderly patients who developed AKI had a higher number of hospitalizations (underlying frailty), were more likely to progress to more severe stages of CKD and to be affected by other non-renal pathologies (associated comorbidities) and to be given heavier pharmacological prescriptions (polypharmacy).